Electronic control units are being used in increasing numbers in the automobile sector nowadays. They are used in modern motor vehicles as engine control units, control units for the ABS system, for releasing the airbag etc. For electric drive vehicles under development, it is necessary to develop battery packs that have an associated battery management system. The battery management system is a system of control units using software to monitor battery operation. Depending on the requirements of the particular customer or available installation spaces in the motor vehicle, the topologies of battery packs are extremely varied in terms of the number of battery cells, battery modules, sensors or the like.
Typical battery management systems in general ensure safe and reliable operation of the battery cells and battery packs. They monitor and control currents, voltages, temperatures, insulation resistances and other variables for the battery cells and for the entire battery pack. These variables can be used to implement management functions, which can significantly increase the lifetime, reliability and safety of the battery system.
Battery management systems typically comprise a multiplicity of control units, in which run various implemented software functions. The number of battery cells, the number of sensors and the allocation of the battery modules to different installation spaces on the vehicle determine a resultant control unit topology that comprises a battery control unit (BCU) and a number of lower-level sensor control units for acquiring measurement data. The measurement data to be acquired includes in particular voltages, temperatures and currents, which are measured directly at the individual battery modules. The acquired measurement data is generally transferred between the individual control units, i.e. the sensor control units, and the battery control unit via a communications bus, which in particular may be a CAN bus.
DE 10 2006 048 555 A1 discloses a control unit. Said control unit comprises a first integrated circuit, which includes a microcontroller and a programmable memory, and at least one further integrated circuit, which comprises hardcoded identification information. The programmable memory of the first integrated circuit contains checking information, which allows verification of the identification information.
Although identical sensor control units are used in different projects, they are provided with different data depending on the project parameters, and this difference concerns the voltage and current limits, which depend on the power data for the battery cells being used. It must therefore be ensured that sensor control units can be replaced without detection by the battery control unit (BCU) of the battery management system. By installing a new sensor control unit, which is designed for more powerful batteries, the battery may be operated illicitly outside the specification, which would enable, for instance, “tuning” by the end customer. For safety reasons and in particular for warranty reasons, such a replacement must be detected and prevented. On detecting an unauthorized replacement of a control unit, in particular of a sensor control unit, the battery management system can inhibit use of the relevant battery pack in which the replacement has taken place.